杭电acm2502

2^(n-1)+之前所有情况之和

#include <stdio.h>#include <math.h>int main() {int n, i, t, k, j[22]={0, 1};scanf("%d", &n);k = 1;for(i=2; i<22; k+=j[i++]) {j[i] = k + pow(2, i-1);;}while(n--) {scanf("%d", &t);printf("%d\n", j[t]);}return 0;}